The present invention relates generally to a laryngoscope, and more particularly to a laryngoscope including a blade which is upwardly curved and includes a downwardly directed tip portion for use in intubating a patient with a flexible endotracheal tube.
The use of a laryngoscope for the intubation of a patient, as well as its use in other procedures, is well known in the art. FIG. 1 illustrates one typical prior art laryngoscope, generally indicated by reference numeral 10. Laryngoscope 10 is shown in its normal operative downwardly directed position and includes a handle 12 extending upward (to be held by the operator) and an upwardly curved tubular blade 14 which are disengagably connectable with one another. Blade 14 includes a proximate end 16 and a distal end 18. Distal end 18 includes a tip portion 20 which forms the leading end of the blade. The blade also includes a tube passage (not shown) which extends from the proximate end to the distal end of the blade. The tube passage has an entrance opening 24 at the uppermost end of the blade and an exit opening 26 at the distal end of the blade. A light source (not shown) located in the handle provides light to a proximate end 28 of a fiber optic lighting member 30 carried by blade 14. Light received by fiber optic member 30 is transmitted to its distal end 32 to illuminate tip portion 20 of the blade and the anatomy of a patient (not shown) adjacent the tip portion when the laryngoscope is in actual use. A fiber optic viewing member 34 including an end 36 cooperates with the lighting member to provide for remote viewing at the tip portion using an eyepiece 38.
Still referring to FIG. 1, an endotracheal tube 40 is shown inserted through entrance 24 and on through the tube passage provided by the blade such that a leading end 40a of the tube extends outwardly from exit opening 26. The upward curvature of the blade near distal end 18 is specifically provided to best cooperate with the pharyngeal passage of a typical patient. This curvature, as illustrated, is generally approximately circular and is carried through tip portion 20 of the blade.
While the prior art laryngoscope, as depicted in FIGS. 1, is generally satisfactory for its intended purpose, there is a particular aspect of the instrument, as shown and described above, which may be improved upon in accordance with the present invention, as will be discussed below.
Referring once again to FIG. 1, it should be noted that endotracheal tube 40 is flexible in order to pass through the curved laryngoscope blade and in its relaxed state the tube maintains a radius of curvature which is greater than that of the distal end curve of the blade. Therefore, leading end 40a of the tube tends to follow a path upon emerging from tube passage 26 at the distal end of the blade which follows its own larger radius of curvature rather than the smaller curvature of the distal end. As a result, as leading end 40a emerges from distal end 18, it separates from tip portion 20 rather than hugging up against it, thereby defining an acute angle A therebetween. This downward curvature is caused in part by gravity along with the natural tendency of the somewhat resilient tube to want to bend back to its larger radius of curvature. A space 46 is thereby formed between the tube and adjacent tip 20 of the blade as defined by acute angle A. This separation at space 46 can lead to problems in an intubation procedure, which will be described immediately below.
A first problem resulting from the divergence or spacing between the tube and the tip portion occurs with regard to lighting member 30 and viewing member 34. Distal end 32 of the lighting member is fixedly attached to the blade and aimed to illuminate an area along tip portion 20. Similarly, end 36 of the viewing member is also fixedly aimed along the tip portion. In most cases, since the field of view through a fiber optic member is limited, leading end 40a of the tube will move out of the field of view of the viewing member or out of the area which is illuminated by the lighting member as the tube diverges from the tip portion in a downward direction. The benefit of the viewing member is thus lost at the critical point of the intubation procedure when it is desired to place the tube into the trachea.
If the spacing between leading end 40a of the tube and tip portion 20 is sufficiently great, in order to compensate for the spacing, the health care practitioner may have to manipulate the end of the blade in certain ways in order to properly align the tube with the patient's trachea.
As will be seen hereinafter, the present invention provides a solution for the problems caused by the emerging leading end of the tube diverging from the tip portion of the blade.